(a) Field of the Invention
This invention relates to a strengthened and improved structure for a hydraulic jack, which is constructed mainly by providing a drive bracket and a blocking piece at the proper location in the inner side at each side board of the frame body of the hydraulic jack for mounting of the hydraulic cartridge via its semicircular cylindrical base to the frame body of the hydraulic jack. A quick dismounting/mounting means is provided inbetween the hydraulic cartridge and the frame body of the hydraulic jack, therefore, the hydraulic cartridge can be quickly dismounted/mounted when repair is required, also the frame body is strengthened by welding process, which prevents it from eccentric loading deformation, whereby, a sturdy and safe hydraulic jack is constructed.
(b) Description of the Prior Art
In the traditional hydraulic jack, the hydraulic cartridge is mounted with its base on a through-axle. This through-axle is then mounted on a frame body which consists of two side plates and is tightened together along with the hydraulic cartridge by bolts and nuts. From a structural point of view, the traditional hydraulic jack contains too many jointing points, fasteners, bolts, nuts, and the like. Therefore, when it is loaded, the load weight will be distributed in proportion to each of the above jointing points and component parts, and in a case of the saddle of the hydraulic jack being eccentrically loaded, even if the load weight is within the load specifications of such a hydraulic jack, the induced moment and shearing force will be absorbed completely by the above jointing points and component parts to make them loosen. Even if the condition is less serious, the above-named component parts will become deformed thus affecting the subsequent dismounting or adjustment of the works. But if the condition is quite serious, the whole hydraulic jack collapse, thus, endangering the user or causing damage to the load. In order to eliminate the above shortcomings while providing a strengthened, sturdy, and quick dismounting/mounting hydraulic jack, the first thing one has to do is to reduce the jointing points of the relevant component parts which constitute the frame body of the hydraulic jack. Thus, the most desirable design is to construct the frame body of the hydraulic jack into a whole and integrated body, i.e. all jointing points are replaced by welding process to enhance the load bearing structural strength of the frame body. However, in a traditional hydraulic jack, no matter whether its frame body is jointed by bolting or welding the relevant parts together, the hydraulic cartridge is always mounted on the frame body with its base via a supporting through-axle by screw nuts. Therefore, if it is necessary that repair should be made to the hydraulic cartridge, then the frame body of the hydraulic service jack must be first disassembled; thereafter, the nuts on the through-axle must be removed, then the hydraulic cartridge can be finally dismounted. From the above description, it can be seen that the dismounting procedure for the hydraulic cartridge from the frame body of the conventional hydraulic jack is complex in nature and this constitutes another shortcoming of the traditional hydraulic jack.
In summary, the traditional hydraulic jack has the following shortcomings:
i. The frame body of a traditional jack is joined by a plurality of bolts and nuts. If repair is required owing to parts failure of the hydraulic cartridge such as failure of the oil seal, O-ring, or hydraulic cylinder, or structural component parts damage, such as link assemblies, or linkage rods and the like of the hydraulic jack, it takes time and requires a complex procedure for accomplishing dismounting/mounting work when the bad parts are to be replaced by new ones.
ii. There exist too many jointing points in a traditional hydraulic jack. They contribute adversely to its load bearing structural strength, whereby, it can be easily damaged by shearing force as well as creating safety problems. If all of these jointing points of the frame body are replaced by welding, although the structural strength of the frame body in increased, when the ram plunger or any other parts in the hydraulic cartridge break and require replacement, the repair work can not be easily done because the hydraulic cartridge can not be easily dismounted from the frame body and vice versa.
iii. In the manufacturing process of the traditional hydraulic jack, given that the assembling work of its two side boards into a frame body is both time and labor consuming, and consequently the unit production cost is still not considerably reduced. These all contribute adversely to its market competition ability.